Dental chair



4 Sheets-Sheet 1.

(No Model.)

F- E. CASE. DENTAL 0mm.-

Patented June 30, 1891.

wifmgooeo 4 Sheets-Sheet 2.

(No Model.)

B. CASE. DENTAL CHAIR.

No; 455,168. Patented June so, 1891.

In? 1 x fkva W m: NORRIS runs 00., mom-mum, WASHINGTON, u. c

(No Model.) k 4Sheets-Sheet 3'.

IKE CASE. DENTAL CHAIR.

No. 455,168. Patented June 30,1891.

(No Model. 4 Sheets-Sheet 4. F. .13. CASE. DENTAL CHAIR.

No.455,168. PatentedJune30,189 1 qmmwm,

UNITED STATES PATENT OFFICE.

FRANK E. CASE, OF CANTON, OHIO.

ENTAL CHAIR.

SPECIFICATION forming part of Letters Patent No. 455,168, dated June 30,1891 Application filed October 22, 1889- Serial No. 327,758. (No model.)

- in the county of Stark and State of Ohio, have invented certain newand useful Improvements in Dental Chairs, of which the following is afull, clear, and exact specification.

This invention relates to dental chairs, and has for its objects toprovide novel means for raising and lowering the chair-body; to providenovel means whereby the chair-body can be rotated and inclined backwardand sidewise; to provide novel means for placing the back in thereclining or horizontal position; to provide novel means for raising.and lowering the back independent of the seat; to provide novel meansfor governing the speed of the chair-lowering screw; to provide novelmeans for raising and lowering the step and foot-rest independent of theseat; to provide novel means whereby the step and foot-rest can beadjusted by the dentist through the medium of the chair-back, andthereby avoid undignified stooping; to provide a novelheadrest which isadjustable to various posit-ions, as occasion may render desirable, andto provide novel means for adjusting the foot-rest forward and backward,as treatment or manipulation by the dentist may require, and tootherwise improve and render dental chairs more useful, desirable, andefficient.

To accomplish all these objects, my invention involves the features ofconstruction, the combination or arrangement of devices, and theprinciples of operation hereinafter described in detail, andspecifically set forth by the claims, reference being made to theaccompanying drawings, in which Figure 1 is a perspective view of adental chair embodying my invention, showing all the parts in normalposition or adjustment. Fig. 2 is a detail perspective view of thechairbase or base-frame. tional view of the same, showing the chair-Seat and portions of the back-support and the step. Fig. 4: is a detailvertical sectional view of the rising and falling standard. Fig. 5' is adetail perspective view of the brakelever for locking the chair-loweringscrew against rotation. Fig. 6 is a detail perspective view showing thebase-frame, the slid- Fig. 3 is a vertical sec-' ing standard, thebracket, and the balancewheel and screw separated from each other. Fig.7 is a detail perspective view of the yoke-hub or frame for connectingthe chairbody with the chair-base. Fig. 8 is a detail perspective viewof'the nut for the yokehub or frame. Fig. 9 is a detail brokenperspective view showing a portion of the backsupport and the chair-seatframe withoutnp- 6o bolstering. Fig. 10 is a detail perspective view ofone of the side arm supports. Fig.

11 is a detail vertical sectional view of the chair-back, showing thehead-rest and the means for connecting the back-support with theseat-frame. Fig. 12 is a detail sectional view of the foot-rest, showinga portion of the step. Fig. 13 is a detail perspective view of aport-ion of the chair-body, showing the side arms adjusted to form achilds seat. Fig.-14- is a detail perspective view showing parts of thehead-rest separated from each other. Fig.

15 is a perspective view of a part of a sidearm, showing itsfastening-nut and washer.-

Fig. 16 isva side elevation showing a portion of the chair-base and thedevices for locking the rocking yoke-hub. Fig. 17 is a detail plan viewof the balance-wheel and governor mechanism for regulating the speed ofrota tion of the chair-lowering screw. Fig-1'8 isSo a perspective viewof portions of the lifting-" lever and dog separated from each other.

Fig. 19 is a sectional side elevation showing portions of theback-support and the rear extension of the seat-frame. Fig. 20 is adetail view of a sleeve for rendering a side arm vertica-llyadjustable."

In order to enable those skilled in the art to make and use myinvention, I will now describe the same in detail, referring to the 0drawings, wherein- The numeral 1 indicates the base-frame, whichcomprises supporting-legs, preferably three, suitably spread to providestability and avoid overturnin g the chair. The base-frame 9 5 isprovided with an upright standard 2, a11- gular or V-shaped transverselyat the upper end portion to receive the vertically-sliding tubularstandard 3, confined in place by a bracket 4, which is flat on itsinside and se- I03 cured to the standard 2 by screw-bolts 5, engagingscrcw-holes 7, Fig. 6.

The angular or V-shaped formation of the tubular standard 3 toaccurately fit the correspondingly-shaped standard 2 of the base-frameprovides for the compensation of wear by tightening up the bracket el:through the medium, of the screwbolts 5, it being understood that inassembling the parts the vertical face of the bracket is left a shortdistance from the vertical face of the standard 2, in order to permitsubsequent adjustment of the bracket.

The tubular standard is divided into two 'chambers 8 and 9, one adaptedto receive the screw 10 and the other having within it a vertical row ofteeth forming a ratchet 12,'which is preferably formed integral with thetubular standard. The lower end of the chamber 8 is constructed open orwith an orifice 13, so as to pass over the screw 10, the thread of whichis preferably, but not necessarily, about one revolution to the inch,this screw being rigidly attached at its lower end to ahorizontally-rotatin g balance-wheel 15, having at its under side apivot-bearing 16 on the base part of the bracket e and provided on itsperiphery with an annular series of notches or ratchet-teeth 17. Apendent pawl 18, Fig. a, is pivoted to each side of the tubular standarddirectly beneath the opening 13, and is pressed by a spring 19 to throwthe tooth 20 of the pawl into engagement with the screw. I have shownone pawl detached and one attached in Fig. 4:; but in practice one willbe applied at each side of the screw. The upper end of the tubularstandard is provided with two oppositely-arranged lugs or parts 21, Fig.6, to which are pivoted by suitable pivotscrews 22 the arms 23 of ayoke-hub or frame 24, comprising a tubular neck 25 and an armextension26, having a curved or segmental flange 26, provided with a line of boltor catch orifices 27.

A screw-nut 28 is detachably arranged in a seat 29 in the yoke-hub incoincidence with the vertical opening through the tubular neck 25, andwith this nut engagesthe screw-stem 30, rigidly attached to the lowersection 31 of the seatfram e, whereby the entire chair-bod y,hereinafter described, is supported from the yoke-hub through the mediumof the serevstem 30. This stem may be locked by a screw-bolt 32, tappedthrough a part of the yoke-hub to bind against the screw-stein and holdthe chair-seat stationary as regards rotary movement, while by rotatingthe screwstem the chair-seat can be raised or lowered relatively to theyoke-hub. 'If, however, this vertical adjustment of the chair-seat isundesirable, the screw-nut 28 may be removed and the stem 30 simplyaxially rotate without rising or falling.

To elevate the tubular standard and lock and release the screw operatingconjointly therewith, I provide a lifting-lever 33 and a brake-lever 34,pivoted in or to the rear sup porting-leg, as in Figs. 1, 2, 3, and 6.The lifting-lever 33 is mounted on a pivot-pin 35, and at its forwardend, in advance of this pivot-pin, said lever is pivoted at 36 to avertically-arranged lifting-dog 37, having at its upper end a tooth 3Sto engage theraichet 12. The lifting-dog is provided at its lower endwith a tail-piece 39, so that the dog is approximately L-shaped, and onthis tail-piece bears one end of a spring 4.0, which at its other endbears against the inside of the leg part of the base-frame 1. Thelifting-lever is made at its rear end as a pedal for the foot of thedentist or operator, and the parts are so constructed that when thelifting-dog is-in its normal position its tail-piece 39 rests upon andbears against the upper side of the lifting-lever in advance of thepivot-pin 36. The shape of the connected ends of the lever and dog isbest shown in Fig. 18, where the parts are slightly separated. It willbe evident that when the lifting-lever is depressed by the foot of theoperator the front end thereof is raised, and the spring i0, bearing onthe tail-piece 39, causes the tooth 38 of the dog to move toward andengage the ratchet 12, so that the continued depression of the rear endof the lifting-lever 33 elevates the lifting-dog, and thereby raises thetubular standard for adjusting the chair-body to the desired height,while the spring a0 when the foot is removed from the lifting-leverrestores the latter and the dog to their normal positions for subsequentoperation to again lift the standard.

To lock the standard in its raised position, the teeth 20 of the pawls1S engage the thread of the screw 10, this being efiected by the springs19, for while the pawls can oscillate and yield and ride over thethreads of the screw the toothed ends 20 are promptly thrown intoengagement with the flattened upper sides of the threads, as will bequite obvious, thereby elfectually preventing the descent of the tubularstandard so long as the screw 10 is held against rotation, this beingeffected by the toothed end 41 of the brake-lever 34, which is pivotedin or to the supporting-leg by a pivot-pin 42, located, preferably, inrear of the pivot of the 1ifting-lever.

A spring 43 bears upon the front or toothed end of the brake-lever tothrow the same into engagement with the notched or toothed part 17 ofthe balance-wheel 15, and the rear end of the brake-lever is made as apedal, so that the dentist or operator can depress the same, and therebylift the front or toothed end of the brake-lever from engagement withthe balance-wheel.

The tubular standard can be more or less engaging the threads wouldrotate the screw, except for the holding orbraking action of thebrake-lever on the balance -wheel, and consequently when the rear end ofthe brakelever is depressed and the. balance -wheel thereby released theweight alluded to causes the screw to rotate, whereby the tubularstandard and chair-body descend gradually and withoutshock the requireddegree, subject to the length of time the brake-lever is held out ofengagement with the balancewheel, for the instant the brake-lever isreleased it engages and locks the balance-wheel against furtherrotation. The spring-pawls 18 act as an open nut to permit an ascendingmovement of the tubular standard without rotation of the screw 10, butprevent a descending movement of the standard, except by rotary movementof the screw, as explained. By the means described the operator isenabled to raise the chair by the lifting-lever and to lower the same bysimply depressing the brake-lever.

To regulate the speed of the balance-wheel in the descent of the chairand prevent too rapid rotation of the screw 10, I provide a speedgovernor comprising features which are best shown in Fig. 17, where thenumerals 44 indicate brake-shoes, of which there may be any suitablenumber, but preferably three, pivoted near one end portion, as at 45, tothe under side of the balance-wheel, so that each shoe compriseswhat Iwill term a heel 46 and a toe 47.

A rigid and immovable friction ring or annulus 48 is arranged beneaththe balancewheel to co-operate with the brake-shoes, and

this ring is preferably attached to or made as i a part of thehorizontal portion of the bracket 4, Fig. 3, in such manner that thering projects into the space between the brake-shoes. As thebalance-wheel revolves the tendency of the toe ends 47 is toautomatically fly outward, and thus force the heel ends 46 against theexternal surface of the immovable friction ring. The more rapidly thebalancewheel revolves the greater is the centrifugal force imparted tothe toe ends 47 and the more firmly are the heel ends 46 pressed againstthe friction-ring, thereby retarding the speed of the balance-wheel andpermitting only a uniform rotary movement of the wheel and screw.

The screw-stem 30 is useful to provide for considerable elevation of thechair-body without correspondingly increasing the height of thebase-frame 1 and the length of the tubular standard 3, which increasewould not permit the chair-body to' be lowered sufficiently foroperating on the patient with convenience.

The chair-body comprises, in general, a seat 49, back 50, side arms 51,astep 52, a foot-rest 53, and a step-support 54, all properlyupholstered or otherwise finished in any manner that may be desired orconditions require,

The lower section 31 of the seat-frame is provided with two pendentflanges 55, one at either side, connected by pivot pins or bolts 56 tolevers 57, having their front ends pivoted at 58 to the side bars 59 ofthe step-support 54, said levers 57 extending back to the rear side ofthe chair-seat, where they converge, unite, and extend rearward as acentral arm 60. The side flanges 55 are also pivoted, as at 55, to therear ends of the levers orlinks 61, having their front ends pivoted at62 to the upper ends of the side bars 59, the said links being placedabove the levers 57.

The lower section 31 of the seat-frame is provided with a pair ofrearwardly-projecting arm-extensions 63, one at either side, to whichare respectively pivoted at 64 and 65 the branch arms 66 and 67 of aback-support 68, the branch arm 66 extending lower than the one 67 andat its lower extremity having a screw-threaded orifice, Fig. 19, withwhich engages a screw-rod 69, extending through a segmental slot 70 inone of the arm-extensions 63 and provided with a crank-handle 71 and acollar or flange 7 2 to bear against the slotted arm-extension 63, Fig.9. The crank-handleser'ves to rotate the screw-rod, and if the latter isloosened the back-support 68 may be turned on the pivot-pins 64 and 65and adjusted forward or backward to any desired angle of inclination andthen looked in its adjusted positionby tightening the screwrod 69, whichthereby rigidly clamps the branch arm 66 to the slotted arm-extension 63by means of the collar or flange 72.

To the back 50 is rigidly attached a hollow frame 7 3, in which isarranged a standard 74, Figs. 9 and 11, triangular or approximately soin cross-section and passing through and .movable lengthwise in acorrespondinglyshaped socket 7 5 in the back-support 68 This standard ispivotally connected at its lower end with the arm-extension 60 of thelevers 57 through the medium ofa link 76 in such manner that thelengthwise movement of the standard oscillates the levers for adjustingv the step-support and the step, as will be more fully describedhereinafter. The back-frame 73 has a limited vertical movement onthestandard 74 and is provided with aset-screw 77 to bind against thelatter and hold the back in a fixed position relatively to the standard,so that the back and standard can be moved in unison. The standard andthe back-support can be rigidly connected by a set-screw 78, tappedthrough the socket 75 to bind against or engage the standard, and ifthis set-screw be loosened the back is adapted to slide up or down,carrying with it the standard and oscillating the levers 57, and as thelatter are fulcrumed or pivoted at 56 a reverse movementisimparted tothe step-support 54. For v instance, as the back is lowered thestep-support is elevated, and vice-versa. As the two levers 57 and G1are pivoted to either side of the chair, as at 55 and 55, and to thestepsupport, as at 58 and (52, at points about equally distant from eachother, the step-support is preserved approximately vertical in itsrising and falling movements, and consequently when the sliding standard74 is secured in a fixed position by its locking setscrew 7 S thestep-support is held stationary, and as the step-support carries thestep 52 the latter is also held in a fixed position as regards verticalmovement. The step comprises side fianges 79, which are pivoted at tothe lower ends of the side bars 50 of the step-support, so that whilethe step is sustained in an approximately horizontal position when inuse it can be swung up against the step-support for convenience inshipping. By the mechanism described the operator can raise and lowerthe step by vertical movements of the chair-back, and as. the step isdesigned tocarry the f0ot-rest 53 the position of the latter is alsocontrolled by the vertical movement of the back.

The foot-rest 53 is supported at the ends by standards 81, which attheir lower ends underlie the flanges 79 and serve as bearings, as at82, for a rotating shaft 83, having at the ends rigidly-attached pinionsor cog-wheels Set, housed in the parts 82, and engaging racks 85,provided on the under sides of the flanges 79, Fig. 12, and along whichthe pinions or cogs can travel back and forth in engagement with theracks, so that as the end of the foot-rest is forced backward or forwardby the operator from either side the pinion or cog-wheel at the endoperated upon is caused to rotate, and thereby impart a correspondingrotary motion to the opposite pinion or cog-wheel, thereby accuratelymoving both ends of the foot-rest in unison and avoiding all tendency ofbinding.

The section 31 of the seat-frame is provided with a rectilinear channelor recess 86, running transversely from sideto side, Fig. 0, in whichare placed the horizontal portions 87 of the arm-supports or standards88 for the side arms 51, Figs. 1 and 13, which portions 87 each have arectangular slot 80, provided at one edge with a series of gear-teeth 90to engage a rotary pinion 01, journaled centrally in the rectilinearchannel or recess 86, Figs. 3 and. 9. The gear-teeth of one arm-supportare on the rear edge of its slot, and the geartceth of the other arm-support are on the front edge of its slot, and consequently themovement of one arm-support correspondingly moves the oppositearmsupport, the arrangement being such that one of the horizontalportions 87 overlies and moves upon the other. By this means theoperator is enabled by moving one side arm in or out to simultaneouslymove the other to a correspondin g degree in or out for increasingordecreasing the distance between the side arms, which is very useful ina dental chair.

The vertical parts or standards of the armsupports are each providedwith a rib 92, Figs. 9 and 10, to fit a corresponding groove in a sleeve93, Figs. 1, 13, and 20, formed with or attached to the lower section 91of a side arm 51 and having a set-screw 95 tapped through the sleeve tobind against the outer face of the arm-support, whereby the side arm hasa limited vertical adj ustmentto vary its height relatively to thechair-seat.

The upholstered upper sections of the side arms are coextensive with andrest upon the lower sections 94, and each upper section is provided witha screw-stem 96, Fig. 15, to pass through a slot 97, formedwlengthwiseof the lower section Set, and engage a washer 08 and a thumb-nut 99 forclamping or binding the two armsections together, while by loosening thenut the stem serves as a pivot for swinging the upper arm-sections atright angles to the lower sections to extend across the chair, as inFig. 13, thereby providing a childs seat, which is convenient in adental chair. \Vhen the upper arm-sections are adjusted across thechair, the free end of one rests upon the opposite lower arm-section,and therefore the seat so provided can be raised or lowered by adjustingthe sleeves 03.

In Figs. 1, 11, 13, and 14 is shown a headrest 100, having ears 101 onits rear side, to which are pivoted pendent links 102, provided withlongitudinal slots 103 to engage a horizontal screw-bolt 104, passingthrough a head on a shank 105, which is circular in cross-section andfits a socket-bearing in the upper end of the frame 73 on the back 50,where the shank is adjustably secured by a set-screw 106, tapped throughsaid frame to bind against the shank. The head of the shank comprises arigid cross-bar 107, preferably oval in cross-section and formed with orattached to the shank, such cross-bar having a longitudinal slot 108,receiving the lugs on the inside of two washers 110, havingthrough-orifices 112 for the passage of the screw-bolt 104. This boltextends through the slotted links 102, the washers, and the crossbar,and on its threaded end is placed a thumb or wing nut 113, so that bytightening the latter the washers and the links are rigidly clamped tothe cross-bar for holding the head-rest stationary in relation thereto.The axial rotation of the shank provides for turning the head-rest tothe right or left, and also raising and lowering the same in a rightline, while by loosening the thumb or wing nut 113 the head-rest may beslid backward or forward 011 the cross-head or swung with the linksbackward or forward anu raised and lowered, the links moving on thescrew-bolt back and forth and up and down. The parts are rigidly held inany adjusted position by tightening the thumb or wing nut 113 and theset-screw 100. The upper ends of the links 102 are bent in oppositedirections for pivoting with the ears 101, which, as shown in Fig. 14,are near dilferent corner portions of the head-rest. The lugs of thewashers are of a thickness somewhat less than the slot in the cross-bar,so that the washers laterally or sidewise.

can be slightly turned or rotated on the crossbar to set the head-restmore or less inclined to the right or left.

It is desirable in a dentist-chair to give the entire chair-body abackward inclination on the base-frame, especially if it be necessary toplace the head of the patient below the horizontal position, and it isalso desirable to provide for tilting or inclining the chair-body Theseresults I accomplish by the yoke-hub 24 in the manner and by the meanswhich 1 will now describe. The yoke-l1 ub, as hereinbefore explained,embraces and is pivoted to the upper end of the vertically-slidin gstandard 3, and the arm-extension 26 can oscillate beside aforwardlyprojecting arm 114, formed with or attached to the upper endportion of the sliding standard, Figs. 3, 4, 8, and 16. The arm 114 isprovided at its outer end with a lateral segmental flange 115,conforming to and underlying the curved face 26 of the arm-extension26,Figs. (i and 16, and the flange is provided with an opening 116, Fig.6, adapted to register with any one of the orifices 27 in such mannerthat a 1ocking-bolt 117 can enter an orifice for rigidly connecting theyoke-hub with the arm of the sliding standard, while, if the lockingboltbe retracted from engagement with one of the orifices 27 the yoke-hubcan be oscillated or rocked in a vertical plane to incline thechair-body backward, and thereby lower the head of the patient therequired extent; The locking-bolt 117 slides in a keeper 118, on the arm114, and is thrown into locking position by a spring 119, and toconveniently retract the bolt a lever 120 is pivoted at 121 on the arm114 and connected with the bolt. The bolt-actuating lever is preferablyarranged that its lower end may be pressed upon by the foot of theoperator at a point near one of the chair-supporting legs. The lateralor sidewise inclination of the chairbody is effected in a very simpleway, as will be quite obvious by assuming that when the parts are in theposition shown in Fig. 3 the entire chair-body extends in a planeparallel with a line drawn centrally between the arms 23 of theyoke-frame, and that by turning the chair-body one-quarter of arevolution through the medium of the screw-stem 30 the chair-body as awhole will then extend in a line at right angles to the line drawncentrally between the arms 23 of the yokehub. Consequently if theyoke-hub now be swung upward on its pivots 22 the chairbody is more orless inclined or tilted to the right or left, according to the directionin which the quarterrevolution referred to is made. This will be moreclearly under stood by referring to Fig. 1, where the chairbody extendsparallel to a line drawn centrally between the arms of the yoke-hub. Theyoke-hub is not seen in Fig. 1; but its relative position will beunderstood by reference to Figs. '3 and 6. If now the chair-body as awhole be turned one-quarter of a revolution in the direction of thearrow 0., Fig.1, and the yoke-hub be swung upward, the chairbody Will beinclined or tilted sidewise to the .left, looking from the head-rest,While, on the contrary, if the chair-body be turned onequarter of arevolution in the direction of the arrow Z), Fig. 1, and the yoke-hubsimilarly swung upward, the chair-bod y will be inclined or tiltedsidewise to the right, looking from t ing-pawls on thevertically-movable standard,v

since a single pawl can be used.

Having thus described myinventiou, whatI claim is- I 1. The combinationof a base-frame, avertically-adj ustable standard guided thereby, arocking yoke-hub or frame pivoted to the standard and having ascrew-nut, a seat frame attached to and carrying a chair-back,

, and a screw-stem arranged in the yoke-hub or frame, supporting theseat-frame and back, and serving to rotate and simultaneously raise andlower the chair back and seat, substantially as described.

2. The combination of a base-frame, a vertically-sliding standardguide dthereby, a footlever mechanism for elevating the standard, a yoke-hub orframe pivoted to the standard,

position, as will be- ICC:

oscillating on its pivots in a vertical plane,

and provided with a screw-nut, a seat-frame attached to and carrying achair-back, anda rotary screw-stem arranged in the yoke or frame,supporting the seat-frame and back, and serving to simultaneously raiseand lower the seat and back, substantially as described.

3. The combination of a base-frame, a vertically-adjustable. standardguided thereby, a yoke-hub comprising arms pivoted to the standard and atubular neck containing a screw-nut, a seat-frame attached to andcarrying a chair-back, and a rotary screw-stem engaging the nut,supporting the seat-frame and back, and serving to simultaneously raiseand lower the seat and back, substantially as described.

4. The combination of a base-frame, a vertically-adjustable standardguided thereby, a yoke-hub or frame pivoted to the upper end of thestandard and adapted to swing upward on its pivotal attachment, ascrewnut arranged in the yoke-hub or frame, aseat-frame attached to andcarrying a pivoted swinging back, a rotary screw-stem engaging the nut,supporting the seat-frame and back, and serving to simultaneously raiseand lower the seat and back, and locking mechanism for rigidlyconnecting the yoke-hub or frame to the standard, substantially asdescribed.

5. The combination of a base-frame, a vertically-adj ustable standardguided thereby, a yoke-hub or frame pivoted to the upper end of thestandard and containing a nut, a seatframe attached to and carrying apivoted chair-back, and a screw-stem engaging the nut, solely supportingthe seat-frame and back, and serving to simultaneously raiseand lowerthe seat and back, whereby the seat and back can be rotated and alsotilted or inclined sidewlse, substantially as described.

(3. The combination of a base-frame, a slid ing standard guided thereby,a lifting mechanism for raising the standard, a lowering mechanism whichis independent of the lifting mechanism for gradually depressing thestandard, a rocking yoke-hub or frame pivoted to the standard and havinga screw-nut. a seat-frame attached to and carrying and supporting achair-back, and a screw-stem engaging the nut, supporting the seat-frameand back, and serving to simultaneously raise and lower the seat andback, substantially as described.

7. The combination of a base-frame, a vertically-adjustable standardguided thereby, a rocking yoke-hub or frame pivoted to the standard andhaving a nut, a chair-body, a rotary screw-stem engaging the nut,supporting the chair body, and serving to raise and lower the latter,and a locking device acting on the screwstem to hold it againstrotation, substantially as described.

8. The combination of a base-frame, a vertically sliding standard guidedthereby, a foot-lever mechanism for elevating the standard, a loweringmechanism independent of the lifting mechanism for graduallylowering thestandard, a rocking yoke-hub or frame pivoted to the standard and havinga tubu= lar neck containing a screw-nut,achair-body, a rotary screw-stemengaging the nut, supporting the entire chair-body, and serving to raiseand lower the same, and means forlocking the screw-stem against axialrotation in the tubular neck, substantially as described.

9. The combination of a hollow base-frame, a vertically-adj ustablestandard guided therein, a yoke-hub or frame located outside of anddepending beside the base-frame, pivoted to the upper end of theadjustable standard to oscillate on its pivotal attachment in a verticalplane outside the standard and baseframe, and having a screw-nut, achair-body comprising a seat attached to and carrying and supporting aswinging adjustable back, and a rotary screw-stem engaging the nut andsolely supporting the seat and back, whereby the seat and back can beraised, lowered, and thebaekbe inclined rearward and forward and withthe seat tilted laterally or sidewise,substantially as described.

10. The combination of a base-frame, a vertically-adj ustable standardguided thereby, a rocking yoke-hub or frame pivoted to thy; standard andhaving a screw-nut, a rotary screw-stem engaging the screw-nut, aseatframe rigidly attached to and raised and lowered by and rotatingwith the screw, and a chair-back pivoted to the seat-frame and adaptedto be lowered to a horizontal position, substantially as described.

11. The combination of a base-frame, a vertically-sliding standardguided thereby, a lever mechanism for lifting the standard, a sustainingand lowering mechanism independent of the lifting mechanism forsustaining the standard and gradually lowering the same, a yoke-huh orframe pivoted to the standard and having a screw-nut, aseat-frameattached to and-carrying and supporting a chair-back, and a rotaryscrew-stem engaging the nut, supporting the seat-frame, and serving tosimultaneously raise and lower the chair seat andback, substantially asdescribed.

12. The combination of a basefra1ne,a verticallysliding standard guidedthereby, a le ver mechanism. for lifting the standard, a sustaining andlowering mechanism independent of the lifting mechanism,a rockingyokehub or frame pivoted to the standard, and a chair-body having apivoted swinging back and a stem vertically adjustable and rotating inthe yoke-hub or frame, substantially as described.

13. The combination of a base-frame, a vertically-sliding standardhaving a yielding pawl, a lifting mechanism for elevating the standard,a rotary screw engaging the pawl to sustain and also gradually lower thestandard independent of the lifting mechanism, a yoke-hub or framecarried by the standard, and a chair-body supported by the yoke-hub orframe, substantially as described.

1st. The combination of a base-frame,a vertically-sliding standardhaving a yielding pawl, a lifting mechanism for elevating the standard,a rotary screw having a balancewheel and engaging the pawl to sustainand also gradually lower the standard independent of the liftingmechanism, a rocking yokehub or frame carried by the standard, and achair-body provided with a supporting stem rotating and rising andfalling in the rocking yoke-hub or frame, substantially as described.

15. The combination, with a chair body, of a base-frame, avertically-sliding standard guided thereby and having a yieldingsustaining-pawl, a lifting mechanism for elevating the standard, arotary screw engaging the pawl to sustain and also lower the standard,and over the threads of which screw the pawl slides in the ascent of thestandard, and a brake mechanism for locking the screw stationary,substantially as described.

16. The combination, with a chair-body, of a base-frame, avertically-sliding standard having a yielding pawl, a lifting mechanismfor elevating the standard, a rotary screw engaging the pawl to sustainand also lower the standard and having a balance-wheel, anl a brake-lever for engaging and locking the screw and wheel stationary,substantially as described.

17. The combination, with a chairbody, of

a base-frame, a vertically-sliding standard having a yielding pawl, alifting mechanism for elevating the standard, a rotary screw en gagingthe pawl to sustain and also lower the standard and having a notched ortoothed balance-wheel, and a pivoted brake-lever for engaging thebalance-wheel to hold the wheel and screw stationary, substantially asdescribed.

18. The combination, with a chair-body, of a base-frame, avertically-movable standard guided thereby and having a ratchet,aswinging lifting-lever, a dog carried by the liftinglever to lift thestandard, a rotary screw,'a yielding pawl carried by the standard,adapted to ride over the screw-thread in the ascent of the standard,while the screw stands stationary and to engage and sustain the standardagainst descending, and a brake t'or holding the screw stationary,substantially as described.

19. The combination, with a chair-body, of a base-frame, avertically-sliding standard guided thereby and provided with a pivotedspring-pressed pawl having a tooth, a lifting j mechanlsm for elevatingthe standard, a ro-.

tary screw engaging the pawl-toothand over the thread of which the saidpawl slides in the ascent of the standard, while the screw isstationary, a balance-wheel on the screw, and a brake mechanism forlocking the balancewheel against rotation, substantially as described.

20. The combination of a base-frame, a vertically-sliding standardguided thereby, a footlever mechanism for elevating and lowering thestandard, a rocking yoke-hub or frame pivoted to the standard, achair-body having a stem movable in and supported by the rocklngyoke-hub or frame, means for raising and lowering the chair-supportingstem independent of the yoke-hub or frame, and means for holding thestem against movement, substantially as described.

21. The combination, with a chair-body, of a base-frame having a bracketextending thereunder, a rotary chair-lowering screw having abalance-wheel provided with a pivotbearing on the bracket thereunder,the brakeshoes pivoted intermediate their ends to the under side of thebalance-wheel and having their heel ends thrown inward by the outwardmovement of the toe ends, and a friction-ring located in a fixedposition on the bracket of the base-frame beneath the balance-wheel andat a point between the brake-shoes and the chair-lowering screw,substantially as described.

22. The combination, with a chair-body, a base-tram e, avertically-sliding standard having a ratchet, and a lifting-leverpivoted to the base-frame, of a toothed lifting-dog pivoted to theforward end of the lifting-lever and having a tail-piece which restsupon the up per side of the lifting-lever at a point between thepivot-pins of the lifting-lever and the lifting-dog, and a spring actingto press the tailpiece of the lifting-dog downward upon the upper sideof the lifting-lever, substantially as described.

23. The combination, in a chair, of-a baseframepa seat, a back-support,a back rising and falling on the back-support, a step-support, a step,and connections operated by the sliding movements of the back to raiseand lower the step-support and step, substantially as described.

24. The combination, in a chair, of a baseframe, a seat-trance, aback-support, a back rising and falling on the back-support, levers piv;oted on the seat-frame and oscillated by the rising and falling back,and a step-support suspended from the levers, carrying a step, andmoving up and down in an approximately right line as the levers areoscillated, substantially as described.

25. The combination, in a chair, of a baseframe, a seat, a swingingback-support, a back which can rise and fall independent of any movementof the back-support, a step, and suitable connect-ions operated by therising and falling movements of the back to adjust the step,substantially as described.

26. The combination, in a chair, of a baseframe, a seat-frame, aback-support, a back having a sliding connection with the backsupport torise and fall while the latter remains stationary, a step-supportcarrying a step, and suitable connections operated by the rising andfalling movements of the back on the back-support to adjust thestep-support and step, substantially as described.

. 27. In a chair having a seat and back susceptible of being raised orlowered, a rising and falling step, levers fulcrumed to the seatframeand pivotally connected at the front end to the step-support and at therear end to an arm connected with a vertically-sliding standard, andlinks pivoted to the step-sup.

port and to the seat-frame, substantially as described.

28. The combination, in a chair, of a baseframe, a seat-frame, aback-support, a standard sliding lengthwise on the back-support andcarrying a back, pivoted oscillating levers connected with the standard,and astepsupport carrying a step and suspended from the levers, wherebythe rising and falling movements of the back raise and lower thestep-support and step, substantially as de scribed.

29. The combination, in a chair, of a back susceptible of rising andfalling independent of a swinging movement, levers fulcrumedintermediate their extremities and connected at their rear ends with theback, a step connected with the front ends of the levers and adjustedthereby as the back is raised or lowered, and a locking device forrigidly holding the back against its rising and falling movements.

30. The combination, in a chair, of the suspended step-support, the stephaving side flanges provided with lateral rack-bars, the

foot-rest having end standards extending round the outside of andunderlying the side flanges and rack-bars to form bearings in which is journ aled a rotary shaft, and pinions rigid on the shaft, housed by theunderlying bearings of the foot-rest standards, and engaging therackbars, substantially as described.

31. The combination, in a chair, of a seat frame having a transversechannel in its top surface which is covered by the upholstering, thevertical arm-snpports carrying side arms and having the horizontaltoothed portions overlapping in the transverse channel and superimposedand sliding one upon the other, and a pinion journaled between theoverlapping toothed portions for simultaneously adjusting the side armsto and from each other independent of any movement of the seat,substantially as described.

32. The combination, with the back of a chair, of a head-rest havingpivoted side links, a shank having a slotted cross-head, a pair ofwashers having sliding engagement with the slotted cross-head, a boltpassing 2;

through the links, the Washers, and the crosshead, and means for actingon the bolt to rigidly clamp the links and Washers to the crosshead,substantially as described.

FRANK E. CASE.

\Vitnesses: FANNIE LEVINGER, S. D. NCKELVE'Y.

